A New Two-dimensional Analytical Model for Threshold Voltage in Undoped Surrounding-gate MOSFETs

Based on the fully and exact two-dimensional (2-D) resultant solution of Poisson's equation in oxide and silicon regions, a 2-D analytical model for threshold voltage undoped surrounding-gate MOSFETs is derived. The model show that the threshold voltage degradation agrees well with 2-D numerical simulation results over a wide range of device parameters even when the channel length scaled down to 20nm. Both the thin film and thin oxide are preferred to suppress the short-channel effects (SCEs). Besides providing the physical insight into the device physics, the model also offers the basic design guidance for the SG MOSFETs